Inquiry Into Refraction

• Semicircular transparent dish
• Different liquids (water, baby oil, corn oil, etc)
• Laser ray box
• Diagram sheets (idealy graph paper – 2-3 per group)
• Protractor
• Ruler

Light Properties: Refraction

Name: ______Pd: ______Date: ______

Inquiry Lab: Refraction of Light

Objectives:

• To observe how the path of a light ray changes when it travels from one medium to another
• To compare the light bending properties of different liquids

Materials:

• Semicircular transparent dish
• Different liquids (water, baby oil, corn oil)
• Laser ray box
• Diagram sheets
• Protractor
• Ruler

Procedure:

1. Label your first sheet of paper Activity 1. Place the semicircular dish on the diagram paper.

1. Point the single laser beam at the dish, along the normal (dashed line) to the flat side of the dish. This is an angle of zero degrees. Trace the incoming beam (called the incident ray), label it “1”

1. Trace the beam WITH A RULER that leaves the dish on the curved side (called the refracted ray). Label it “IV 1”

(instructions continue next page)

1. For each trial, increase the angle the incident ray makes with the normal by 10 degrees. Trace the incident ray WITH A RULER and the refracted ray. Label each line (IV 1, IV 2, etc).

1. Measure the angle the refracted rays make with the normal and record in Table 1 (below).

Table 1 – Light passing from air into water

Observations:

1. As the angle of the incident ray was increased, what happened to the angle the refracted ray made with the normal?

1. Did the angle of refraction increase at the same rate as the angle of incidence? Explain.

1. What happens to the refraction angle if you put the laser on the other side of the normal line? (10 degrees away, 20 degrees away, etc). Make a conclusion from your observations.

1. Prediction: Will this observed behavior from Activity 1 continue beyond the angle of incidence of 40 degrees? Why or why not?

1. Test your prediction. Gradually increase the angle of incidence. Locate the refracted ray as you keep increasing the angle of incidence. Was your prediction correct? Explain.

1. Label your second sheet of paper Activity 3. Place the semicircular dish on the diagram paper.

1. Point the single laser beam at the dish, along the normal (dashed line) to the curved side of the dish. This is an angle of zero degrees. Trace the incoming beam (called the incident ray), label it “IV 1”

1. Trace the beam that leaves the dish on the flat side (called the refracted ray). Label it “1”

1. For each trial, increase the angle the incident ray makes with the normal by 10 degrees. You may have to adjust the angle of the laser beam so that it hits the flat side of the dish at the point where the normal is drawn. Trace the incident ray and the refracted. Label each line.

1. Measure the angle the refracted rays make with the normal and record in Table 2 (next page).

Table 2 - Light passing from water to air

Observations:

1. As the angle of the incident ray was increased, what happened to the angle the refracted ray made with the normal?

1. Did the angle of refraction increase at the same rate as the angle of incidence? Explain.

1. Prediction: If a different substance is used instead of water in the dish, how will the results of activities 1-4 be different? Explain and be specific.

1. Redo Activity 1 with two other substances and summarize your results below. (You may draw on the same “activity 1” paper if you use two different colored pencils to reflect each substance. Otherwise, get a new piece and label it Activity 4.)

Turn in this lab packet, and staple your ray drawings to the back of the packet.